A Method for Remotely Sensing Vital Signs of Human Subjects Outdoors

Abstract

After chemical or nuclear leakage or explosions, finding survivors is a huge challenge. Although human bodies can be found by smart vehicles and drones equipped with cameras, it is difficult to verify if the person is alive or dead this way. This paper describes a continuous wave radar sensor for remotely sensing the vital signs of human subjects. Firstly, a compact and portable 24 GHz Doppler radar system is designed to conduct non-contact detection of respiration signal. Secondly, in order to improve the quality of the respiration signals, the self-correlation and adaptive line enhancer (ALE) methods are proposed to minimize the interferences of any moving objects around the human subject. Finally, the detection capabilities of the radar system and the signal processing method are verified through experiments which show that human respiration signals can be extracted when the subject is 7 m away outdoors. The method provided in this paper will be a promising way to search for human subjects outdoors.

Short-Range Vital Signs Sensing Based on EEMD and CWT Using IR-UWB Radar

“…Facing the problems of interference from the environment, Wang et al proposed a combined method in [27], consisting of several general methods to extract periodic signals from noise and clutter, and they also concluded that the performance improvement is not satisfied by using only one method.…”

Short-Range Vital Signs Sensing Based on EEMD and CWT Using IR-UWB Radar

“…As the signal processing proposed in [31], facing the same problems of moving interference of the environment, the combined methods was proposed, which includes several ordinary methods of extracting periodic signal from noise, such as self-correlation, adaptive line enhancer (ALE), blind source separation (BBS), EMD, etc., and concludes the effect is not obvious when only using one of the methods mentioned. For sensing the human subject outdoors in [31], it is necessary to remove interference continuously, so ALE is added to reduce the Gaussian noise signal of the detected respiration adaptively.…”

“…For sensing the human subject outdoors in [31], it is necessary to remove interference continuously, so ALE is added to reduce the Gaussian noise signal of the detected respiration adaptively. But for the remotely sensing vital signs including not only the respiration but heartbeat, the higher SNR improvement is required.…”

Short-Range Vital Signs Sensing Based on EEMD and CWT Using IR-UWB Radar

“…Facing the problems of moving interference from the environment, the combined methods are proposed in [27], which include several ordinary methods of extracting periodic signal from noise such as using an adaptive line enhancer (ALE), blind source separation, empirical mode decomposition (EMD), etc., and [27] concludes that the effect is not obvious when using one method of the mentioned methods. In sensing a human subject outdoors in [27], it is necessary to remove interference continuously, so ALE is added to reduce the Gaussian noise signal of the detected respiration adaptively.…”

“…In sensing a human subject outdoors in [27], it is necessary to remove interference continuously, so ALE is added to reduce the Gaussian noise signal of the detected respiration adaptively. However, for the remotely sensing of vital signs including not only respiration but also heartbeat, higher SNR improvement is required.…”